1. Field of the Invention
This invention relates generally to container opening devices, and more specifically to an improved method and apparatus for opening expendable film magazines.
2. Description of the Prior Art
It is known in the prior art to provide an expendable film cartridge made of plastic or other frangible material of the type generally disclosed in U.S. Pat. No. 3,260,182. The film cartridge comprises front and back members which when joined along a line of separation form a film supply chamber in which a coil of interleaved backing paper and film is located when the cartridge is loaded at the factory, a film take-up chamber rotatably supporting a spool onto which the film is wound, and a hollow intermediate part having an exposure aperture across which the film is advanced from the supply chamber to the take-up spool. The line of separation of the front and back members extends around the cartridge except at those portions of the take-up chamber of the cartridge which embrace grooved flanges at the ends of the take-up spool in light-tight relation. At the line of separation at the outer end of the take-up chamber, the front and back members are secured together only at the ends thereof adjacent the aforementioned take-up chamber portions, the intermediate part of such line of separation having unsecured light-tight interfitting ribs. The intermediate part of the cartridge is preferably provided with one or more notches for identifying the type of film contained in the cartridge.
It is further known in the art as exemplified by U.S. Pat. No. 3,580,443 to provide an apparatus for opening film cartridges of the aformentioned type. In such cartridge opening apparatus, a support mechanism including a spindle holds the cartridge in a predetermined position, a tool having a cutting edge is moved into engagement with the line of separation at the outer end of the cartridge and penetrates the cartridge to produce a crack therein, and means are provided for moving the tool in relation to the housing so that the crack is propagated until the housing is sufficiently opened to permit evacuation of the spool carrying the exposed film. Although such a cartridge opening apparatus is believed to operate satisfactorily, some of the disadvantages of such apparatus are its relatively complicated construction, its large number of precision made parts, and its high cost of manufacture and maintenance. In addition, the propagation of the initial crack in the housing is believed to provide a source of plastic chips which might become inadvertently engaged with the exposed film to scratch or otherwise damage it during the presplicing or processing operations.
It is further known in the art to provide a cartridge opening device having sensing means for sensing notches or the like in the cartridge to determine the type of film contained therein, and if the proper film is sensed to enable the cartridge opening device so that it can be operated to open the cartridge.